Understanding the molecular basis of adaption is one of the central goals in evolutionary biology and when investigated across sister species it can provide detailed insight into the mechanisms of speciation. Here, we sequence the genomes of 34 individuals from three closely related grouse species in order to uncover the genomic architecture of speciation and the genes involved in adaptation. We identify 6 regions, containing 7 genes that show lineage specific signs of differential selection across the species. These genes are involved in a variety of cell processes ranging from stress response to neural, gut, olfactory and limb development. Genome wide neutrality test statistics reveal a strong signal of population expansion acting across the genomes. Additionally, we uncover a 3.5 Mb region on chromosome 20 that shows considerably lower levels of differentiation across the three grouse lineages, indicating possible action of uniform selection in this region.

The cochlear sensory epithelium contains a functionally important triangular fluid-filled space between adjacent pillar cells referred to as the tunnel of Corti. However, the molecular mechanisms leading to local cell-cell separation during development remain elusive. Here we show that EphA4 associates with ADAM10 to promote the destruction of E-cadherin-based adhesions between adjacent pillar cells. These cells fail to separate from each other, and E-cadherin abnormally persists at the pillar cell junction in EphA4 forward-signaling-deficient mice, as well as in the presence of ADAM10 inhibitor. Using immunolabeling and an in situ proximity ligation assay, we found that EphA4 forms a complex with E-cadherin and its sheddase ADAM10, which could be activated by ephrin-B2 across the pillar cell junction to trigger the cleavage of E-cadherin. Altogether, our findings provide a new molecular insight into the regulation of adherens junctions, which might be extended to a variety of physiological or pathological processes.

This study examines whether early growth is important for the short- and long-term survival and development of new firms. For this purpose, we use registry data for a specific cohort of Swedish firms that tracks their development until their exit, or up to 14 years, at which point only 8% of the firms remain. We find growth to be clearly associated with increased survival of the firms, that the number of employees (in the previous year) is positively correlated with survival in following years, and somewhat surprisingly, that subsidiaries face a significantly larger hazard of closure than independent firms.

Magnetic skyrmions are topological spin-textures having immense potential for energy efficient spintronic devices. Here, we report the observation of stable skyrmions in unpatterned Ta/Co2FeAl(CFA)/MgO thin film heterostructures at room temperature in remnant state employing magnetic force microscopy. It is shown that these skyrmions consisting of ultrathin ferromagnetic CFA Heusler alloy result from strong interfacial Dzyaloshinskii-Moriya interaction (i-DMI) as evidenced by Brillouin light scattering measurements, in agreement with the results of micromagnetic simulations. We also emphasize on room temperature observation of multiple skyrmions which can be stabilized for suitable combinations of CFA layer thickness, perpendicular magnetic anisotropy, and i-DMI. These results provide a significant step towards designing of room temperature spintronic devices based on skyrmions in full Heusler alloy based thin films.

Biosensors based on plasmonic nanostructures are widely used in various applications and benefit from numerous operational advantages. One type of application where nanostructured sensors provide unique value in comparison with, for instance, conventional surface plasmon resonance, is investigations of the influence of nanoscale geometry on biomolecular binding events. In this study, we show that plasmonic "nanowells" conformally coated with a continuous lipid bilayer can be used to detect the preferential binding of the insulin receptor tyrosine kinase substrate protein (IRSp53) I-BAR domain to regions of negative surface curvature, i.e., the interior of the nanowells. Two different sensor architectures with and without an additional niobium oxide layer are compared for this purpose. In both cases, curvature preferential binding of IRSp53 (at around 0.025 nm(-1) and higher) can be detected qualitatively. The high refractive index niobium oxide influences the near field distribution and makes the signature for bilayer formation less clear, but the contrast for accumulation at regions of negative curvature is slightly higher. This work shows the first example of analyzing preferential binding of an average-sized and biologically important protein to negative membrane curvature in a label-free manner and in real-time, illustrating a unique application for nanoplasmonic sensors.

Technological advances have increased the availability of genomic data in research and the clinic. If, over time, interpretation of the significance of the data changes, or new information becomes available, the question arises as to whether recontacting the patient and/or family is indicated. The Public and Professional Policy Committee of the European Society of Human Genetics (ESHG), together with research groups from the UK and the Netherlands, developed recommendations on recontacting which, after public consultation, have been endorsed by ESHG Board. In clinical genetics, recontacting for updating patients with new, clinically significant information related to their diagnosis or previous genetic testing may be justifiable and, where possible, desirable. Consensus about the type of information that should trigger recontacting converges around its clinical and personal utility. The organization of recontacting procedures and policies in current health care systems is challenging. It should be sustainable, commensurate with previously obtained consent, and a shared responsibility between healthcare providers, laboratories, patients, and other stakeholders. Optimal use of the limited clinical resources currently available is needed. Allocation of dedicated resources for recontacting should be considered. Finally, there is a need for more evidence, including economic and utility of information for people, to inform which strategies provide the most cost-effective use of healthcare resources for recontacting.

Objectives: Menopause involves hypoestrogenism, which is associated with numerous detrimental effects, including on respiratory health. Hormone replacement therapy (HRT) is often used to improve symptoms of menopause. The effects of HRT on lung function decline, hence lung ageing, have not yet been investigated despite the recognized effects of HRT on other health outcomes. Study design: The population-based multi-centre European Community Respiratory Health Survey provided complete data for 275 oral HRT users at two time points, who were matched with 383 nonusers and analysed with a two-level linear mixed effects regression model. Main outcome measures: We studied whether HRT use was associated with the annual decline in forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). Results: Lung function of women using oral HRT for more than five years declined less rapidly than that of nonusers. The adjusted difference in FVC decline was 5.6 mL/y (95%CI: 1.8 to 9.3, p = 0.01) for women who had taken HRT for six to ten years and 8.9 mL/y (3.5 to 14.2, p = 0.003) for those who had taken it for more than ten years. The adjusted difference in FEV1 decline was 4.4 mL/y (0.9 to 8.0, p = 0.02) with treatment from six to ten years and 5.3 mL/y (0.4 to 10.2, p = 0.048) with treatment for over ten years. Conclusions: In this longitudinal population-based study, the decline in lung function was less rapid in women who used HRT, following a dose-response pattern, and consistent when adjusting for potential confounding factors. This may signify that female sex hormones are of importance for lung ageing.

A new class of exact supersymmetric solutions is derived within minimal d = 6 F(4) gauged supergravity. These flows are all characterized by a non-trivial radial profile for the 2-form gauge potential included into the supergravity multiplet. In particular three solutions within this class are featured by an AdS(3) foliation of the 6d background and by an AdS(6) asymptotic geometry. Secondly, considering the simplest example of these, we give its massive IIA uplift describing a warped solution of the type AdS(3) x S-2 x S-3 fibered over two intervals I-r x I. We interpret this background as the near-horizon of a D4-D8 system on which a bound state D2-NS5-D6 ends producing a surface defect. Finally we discuss its holographic dual interpretation in terms of a N = (0, 4) SCFT2 defect theory within the N = 2 SCFT5 dual to the AdS(6) x S-4 massive IIA warped vacuum.

Shipping emissions are likely to increase significantly in the coming decades, alongside increasing emphasis on the sustainability and environmental impacts of the maritime transport sector. Exhaust gas cleaning systems ("scrubbers"), using seawater or fresh water as cleaning media for sulfur dioxide, are progressively used by shipping companies to comply with emissions regulations. Little is known about the chemical composition of the scrubber effluent and its ecological consequences for marine life and biogeochemical processes. If scrubbers become a central tool for atmospheric pollution reduction from shipping, modeling, and experimental studies will be necessary to determine the ecological and biogeochemical effects of scrubber wash water discharge on the marine environment. Furthermore, attention must be paid to the regulation and enforcement of environmental protection standards concerning scrubber use. Close collaboration between natural scientists and social scientists is crucial for progress toward sustainable shipping and protection of the marine environment.

Recently, a non-local yet possibly UV-complete quantum field theory has been constructed by deforming a two-dimensional CFT by the composite operator JT, where J is a chiral U(1) current and T is a component of the stress tensor. Assuming the original CFT was a holographic CFT, we work out the holographic dual of its JT deformation. We find that the dual spacetime is still AdS(3), but with modified boundary conditions that mix the metric and the Chern-Simons gauge field dual to the U(1) current. We show that when the coefficient of the chiral anomaly for J vanishes, the energy and thermodynamics of black holes obeying these modified boundary conditions precisely reproduce the previously derived field theory spectrum and thermodynamics. Our proposed holographic dictionary can also reproduce the field-theoretical spectrum in presence of the chiral anomaly, upon a certain assumption that we justify. The asymptotic symmetry group associated to these boundary conditions consists of two copies of the Virasoro and one copy of the U(1) Ka-Moody algebra, just as before the deformation; the only effect of the latter is to modify the spacetime dependence of the right-moving Virasoro generators, whose action becomes state-dependent and effectively non-local.

Most of the information about the benefits, safety aspects, and cost effectiveness of pharmacological treatment in the respiratory field has been obtained from traditional efficacy studies, such as randomised controlled trials (RCT). The highly controlled environment of an RCT does not always reflect everyday practice. The collection, analysis, and application of effectiveness data to generate Real World Evidence (RWE) through pragmatic trials or observational studies therefore has the potential to improve decision making by regulators, payers, and clinicians. Despite calls for more RWE, effectiveness data are not widely used in decision making in the respiratory field. Recent advances in data capture, curation, and storage combined with new analytical tools have now made it feasible for effectiveness data to become routine sources of evidence to supplement traditional efficacy data. In this paper, we will examine some of the current data gaps, diverse types of effectiveness data, look at proposed frameworks for the positioning of effectiveness data, as well as provide examples from therapeutic areas. We will give examples of both previous effectiveness studies and studies that are ongoing within the respiratory field. Effectiveness data hold the potential to address several evidentiary gaps related to the effectiveness, safety, and value of treatments in patients with respiratory diseases.

Road transports face increasing societal challenges with respect to emissions, safety, and traffic congestion, as well as business challenges. Truck automation, e.g. self-driving trucks may be utilized to address some of these issues. Autonomous transport vehicles may be characterized as Cyber-Physical Systems (CPS). A drawback is that CPS significantly increase technical complexity and thus introduce new challenges to system architecting.

A product architecture is the interrelation between physical components and their function, i.e. their purpose. Product architectures can be categorized as being modular or integral. The main purpose of a modular architecture is to enable external variety and at the same time internal commonality. Products with a modular architecture are configured from predesigned building blocks, i.e. modules. A stable module, which is a carrier of main function(s) has standardized interfaces, is configured for company-specific reasons, which means it supports a company-specific (business) strategy.

In this thesis, the present state at the heavy vehicle manufacturer Scania, concerning product architecting, modularization, product description and configuration is investigated. Moreover, a new clustering based method for product modularization that integrates product complexity and company business strategies is proposed. The method is logically verified with multiple industrial cases, where the architecture of a heavy truck driveline is used as a test bench. The driveline contains synergistic configurations of mechanical, electrical and software technologies that are constituents of an automated and/or semi-autonomous system, i.e. the driveline may be characterized as a CPS. The architecture is analyzed both from technical complexity and business strategy point of view.

The presented research indicates that a structured methodology which supports the development of the product architecture is needed at Scania, to enable control of the increasing technical complexity in the Cyber-Physical Systems. Finally, configuration rules are identified to be highly important in order to successfully realize a modular product architecture. A drawback with this approach is that the solution space becomes hard to identify, therefore a complete and flexible product description methodology is essential. The results from the case studies indicate that clustering of a Product Architecture DSM may result in a modular architecture with significantly reduced complexity, but with clusters that contain conflicting module drivers. It is also identified that the new modularization methodology is capable of identifying and proposing reasonable module candidates that address product complexity as well as company-specific strategies. Furthermore, several case studies show that the proposed method can be used for analyzing and finding the explicit and/or implicit, technical as well as strategic, reasons behind the architecture of an existing product.

Introduction: Phosphoketolases (Xfpk) are a non-native group of enzymes in yeast, which can be expressed in combination with other metabolic enzymes to positively influence the yield of acetyl-CoA derived products by reducing carbon losses in the form of CO2. In this study, a yeast strain expressing Xfpk from Bifidobacterium breve, which was previously found to have a growth defect and to increase acetate production, was characterized.

Results: Xfpk-expression was found to increase respiration and reduce biomass yield during glucose consumption in batch and chemostat cultivations. By cultivating yeast with or without Xfpk in bioreactors at different pHs, we show that certain aspects of the negative growth effects coupled with Xfpk-expression are likely to be explained by proton decoupling. At low pH, this manifests as a reduction in biomass yield and growth rate in the ethanol phase. Secondly, we show that intracellular sugar phosphate pools are significantly altered in the Xfpk-expressing strain. In particular a decrease of the substrates xylulose-5-phosphate and fructose-6-phosphate was detected (26% and 74% of control levels) together with an increase of the products glyceraldehyde-3-phosphate and erythrose-4-phosphate (208% and 542% of control levels), clearly verifying in vivo Xfpk enzymatic activity. Lastly, RNAseq analysis shows that Xfpk expression increases transcription of genes related to the glyoxylate cycle, the TCA cycle and respiration, while expression of genes related to ethanol and acetate formation is reduced. The physiological and transcriptional changes clearly demonstrate that a heterologous phosphoketolase flux in combination with endogenous hydrolysis of acetyl-phosphate to acetate increases the cellular demand for acetate assimilation and respiratory ATP-generation, leading to carbon losses.

Conclusion: Our study shows that expression of Xfpk in yeast diverts a relatively small part of its glycolytic flux towards acetate formation, which has a significant impact on intracellular sugar phosphate levels and on cell energetics. The elevated acetate flux increases the ATP-requirement for ion homeostasis and need for respiratory assimilation, which leads to an increased production of CO2. A majority of the negative growth effects coupled to Xfpk expression could likely be counteracted by preventing acetate accumulation via direct channeling of acetyl-phosphate towards acetyl-CoA.

Precursor lymphoid neoplasms, namely acute lymphoblastic leukemias (ALL) and lymphoblastic lymphomas (LBL), are characterized by an aggressive proliferation of malignant progenitor B- or T-cells. To improve risk classification at diagnosis, better prognostic and treatment stratifying biomarkers are needed. Altered DNA methylation pattern is a hallmark of neoplastic transformation, and has been employed as a molecular prognostic and predictive marker in various cancers, including hematological malignancies. Our research group previously identified a CpG island methylator phenotype (CIMP) panel that classified pediatric T-ALL patients into prognostic subgroups.

The aim of this thesis was to evaluate distinct DNA methylation signatures in precursor lymphoid neoplasms, and to validate the prognostic value of CIMP classification in separate patient cohorts. Additionally, the biological mechanisms underlying the distinct CIMP methylation signatures in these malignancies were investigated.

The prognostic relevance of CIMP classification was validated in an independent Nordic cohort of pediatric T-ALL patients. Combination of CIMP status with minimal residual disease (MRD) status, could further dissect the high-risk MRD positive T-ALL patients into two CIMP subgroups with significantly distinct outcomes. Furthermore, CIMP classification at diagnosis was shown to predict overall survival in relapsed BCP-ALL patients. CIMP methylation signatures were also identified in T-LBL patients, indicating a broader relevance of CIMP based classification in lymphoid malignancies. Investigating the biology behind CIMP methylation signatures showed the association of CIMP status with the proliferative history of the leukemic cells. A differential transcriptomic analysis revealed a correlation of CIMP subgroups with known T-ALL drivers, as well as with novel genes in T-ALL biology. Finally, we identified distinct DNA methylation patterns and genetic aberrations in T-ALL and T-LBL that might contribute to the different clinical presentation of these two diseases. In conclusion, we validated the prognostic significance of CIMP methylation signature in precursor lymphoid malignancies and identified transcriptomic profiles that associated with the subgroups. DNA methylation is a strong candidate for further risk classification in lymphoid neoplasms and our findings can contribute to the identification of new potential targets for treatment.

BACKGROUND: Nested case-control studies aim to link molecular markers with a certain outcome.Repeated prediagnostic samples may improve the evaluation of marker-disease associations. However, data regarding the benefit of repeated samples in such studies are sparse. We aimed to assess the relationship between blood levels of various proteins and risk of glioma, B cell lymphoma, and multiple myeloma to gain further understanding of disease etiology and to evaluate the clinical relevance of the studied markers. To this end, marker-disease associations were evaluated considering the natural history of the studied disease and the time between blood sample collection and diagnosis using both single (I-II) and repeated prediagnostic blood samples (III-IV).

PATIENTS AND METHODS: We conducted four nested case-control studies and one meta-analysis using samples from three prospective cohorts: the Janus Serum Bank, the Northern Sweden Health and Disease study, and the European Prospective Investigation into Cancer and Nutrition study. The following studied endpoints and relationships were included: I) glioma risk and the association with the receptor tyrosine kinases (soluble) sEGFR and sERBB2; II) B cell lymphoma risk and the association with the immune markers sCD27 and sCD30; III) B cell lymphoma risk and the association with immune markers (CXCL13, sTNF-R1, sCD23, sCD27, and sCD30) and their trends over time; and IV) multiple myeloma risk and the association with ten immune markers and growth factors (MCP-3, MIP-1α, MIP-1β, VEGF, FGF-2, fractalkine, TGF-α, IL-13, TNF-α, and IL-10) and their trends over time.

RESULTS: Risk of developing I) glioma was weakly associated with high blood levels of sERBB2. In addition, high levels of both sEGFR and sERBB2 assessed 15 years before diagnosis were associated with glioblastoma risk.

Risk of II) B cell lymphoma was associated with high levels of sCD30, whereas high levels of sCD27 were particularly associated with risk of chronic lymphocytic leukemia. Meta-analyses showed consistent results for sCD30 across cohorts and lymphoma subtypes, whereas results for sCD27 were less consistent across cohorts and subtypes.

In addition, III) B cell lymphoma risk was associated with levels of CXCL13, sCD23, sCD27, and sCD30 assessed in samples collected 17 years before diagnosis. Marker levels increased in cases closer to diagnosis, particularly for indolent lymphoma with a marked association for chronic lymphocytic leukemia and sCD23. Increasing marker levels closer to diagnosis were also observed for CXCL13 in future diffuse large B cell lymphoma patients.

Risk of IV) multiple myeloma was associated with low levels of MCP-3, VEGF, FGF-2, fractalkine, and TGF-α. Levels of these markers decreased in myeloma cases over time, especially for TGF-α. TGF-α assessed at time of the prediagnostic repeated sample seemed to help predict progression to multiple myeloma.

CONCLUSIONS: Both the natural history of the studied disease and the time between sample collection and diagnosis are crucial for the evaluation of marker-disease associations. Using repeated blood samples improves the understanding of marker-disease associations and might help to identify useful biomarker candidates.

Nordic native microalgal strains were isolated, genetically classified and tested for their ability to grow in municipal wastewater. Eight of the isolated strains could efficiently remove nitrogen and phosphate in less than two weeks. Two of these strains, Coelastrella sp. and Chlorella vulgaris, were found to have high biomass concentration and total lipid content; also two Desmodesmus sp. strains showed desirable traits for biofuel-feedstock, due to their fast growth rates and high oil content.

The adaptation to subarctic climate was comparatively evaluated in three Nordic strains (C. vulgaris, Scenedesmus sp. and Desmodesmus sp.) and a collection strain (S. obliquus). Their growth performance, biomass composition and nutrients removal was investigated at standard (25°C) or low temperature (5°C), under continuous light at short photoperiod (3 h light, 25°C) or moderate winter conditions (6 h light, 15°C). Only the Nordic strains could grow and produce biomass at low temperature, and efficiently removed nitrogen and phosphate during both cold- and dark-stress. Phenotypic plasticity was observed in Scenedesmus and Desmodesmus under different growth conditions, adaptation to low temperature increased their carbohydrate content. Short photoperiod strongly reduced growth rates, biomass and storage compounds in all strains and induced flocculation in C. vulgaris, which, however, performed best under moderate winter conditions.

The symbiotic relationships between the Nordic microalga C. vulgaris and the naturally co-occurring bacterium Rhizobium sp. were investigated batchwise under photoautotrophic, heterotrophic and mixotrophic conditions, comparing the co-culture to the axenic cultures. The photoautotrophic algal growth in BG11 medium mainly supported Rhizobium activity in the co-culture, with no significant effects on C. vulgaris. In synthetic wastewater, a synergistic interaction only occurred under mixotrophic conditions, supported by CO2/O2 exchange and a lower pH in the culture, resulting in higher biomass and fatty acids content and more efficient wastewater treatment in the co-culture. Under heterotrophic conditions, the lower biomass production in the co-culture suggested a competition for nutrients, although nutrients removal remained efficient.

A pilot-scale high rate algal pond (HRAP) located in Northern Sweden was inoculated with the collection strain Scenedesmus dimorphus UTEX 417 and operated from spring to autumn. Using metabarcoding of 18S and 16S rRNA genes, the microbial diversity of eukaryotic and prokaryotic communities was revealed. S. dimorphus was initially stable in the culture, but other microalgal species later colonized the system, mainly due to parasitic infections and predation by zooplankton in summer. The main competitor algal species were Desmodesmus, Pseudocharaciopsis, Chlorella, Characium and Oocystis. Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the most abundant bacterial phyla in the HRAP. The structure of the microbial communities followed a seasonal variation and partially correlated to environmental factors such as light, temperature and nutrients concentrations.

Overall, these results contribute with new knowledge on the establishment and optimization of microalgal-based wastewater treatment systems coupled with biomass generation in Nordic areas. The use of native microalgal species is proposed as a potential strategy to overcome the limitations posed to algal cultivation in subarctic regions.

The over all aim for the project in which this paper is anchored is to investigate relationships between teachers’ identity constructions, conditions in local school contexts and changes in educational systems. In this paper I focus on how changes in the educational policy context relate to memories (re-) produced in a local context. The specific aim of this paper is to show how discursive fragments and/or nested narrative types stand out in institutional memories in a local school context.When identities are analyzed time is an important factor, that’s why I consider institutional memories (Linde, 2009) an object of major interest in this study. These memories are known to everybody in the institution and they are constantly told and retold by it’s members. It is a working memory with influence on the identities produced in the institution. The content of institutional memories typically deals with turningpoints in the past, and the founder of the institution. In times of change these memories serve as guides to future actions, but at the same time new aspects are added in the new versions of the memories. These aspects are characterized by narratives, or fragments of narratives, shaped in the time of the telling. In our time there is a substantial influence of private interests in the educational policy context. The new ‘meta’- narrative have been described as a marketization of the educational sector on all levels, with implications for teachers professional identities (Hargreaves, 2006). In this new educational ‘quasi’- market new and old actors meet in different ways in different places. This development put a new focal point on the localities where new narratives about education are told. In his description of exellent clusters Ball (2007) show how discursive fragments moves back and forth between governments and local innovation hot spots in the process of forming new narratives of ‘what works’. These fragments, as told by Ball, are pervaded by neo-liberal ideas. In my data I also trace other, less dominant, ‘meta’- narratives and to describe them I adopt the notion of ‘nested narrative types’ from Linde (2009). My intention in using this notion, is to describe those narratives about education that no longer have, or never have had, a dominant or hegemonic position, but still stands out in the institutional memories. The empirical foundation in which this study is anchored is based on 15 lifehistory interviews conducted with 8 teachers who have been working at the same high school during two years or more. The school was recently shut down and the narratives of the teachers covers the 40-year period when the school was in use. All interviews have been transcribed in detail and screened for institutional memories. Different versions of the memories have been analyzed with respect to discursive fragments and nested narratives.Our results show that versions of institutional memories in a local school context offers different possibilities for teachers to position themselves in relation to different ‘meta’- narratives, or fragments of narratives, about education.

Wood used outdoors is often degraded and discoloured by microorganisms as a natural part of its life cycle, particularly when exposed to high levels of moisture for prolonged times. In this case, the application of a coating (i.e. paint) is an option for increasing the service life of the wood.

Norway spruce (Picea abies (L.) Karst.) is commonly used for outdoor applications in Sweden. Earlier studies have shown that uncoated spruce heartwood is less prone to moisture sorption in outdoor exposure, resulting in lower moisture content (MC) levels, as compared to sapwood. However, studies related to the above mentioned characteristics are rather limited for coated spruce, especially including the influence of outdoor exposure (i.e. weathering).

The aim of this thesis is, therefore, to increase the knowledge of how heartwood and sapwood of different densities influence on the durability of coated Norway spruce for outdoor use. Different types of coatings with alkyd-, acrylic-, flour- (calcimine paint), or linseed-oil-based resin were included. The objectives were to study the water sorption (including MC variation) behaviour and crack formation of uncoated and coated heartwood and sapwood of different densities.

Furthermore was an objective to study the microbial growth on the surface of similar samples of coated spruce in outdoor exposure. The used methods included wetting and liquid permeability experiments, accelerated water absorption (with samples floating freely in water), and outdoor field test. The field method lasted between three to five years and involved monitoring of the MC variation, the crack formation and the microbial growth on the samples.

The results based on wetting measurements using octane as the adsorbed liquid showed no difference in liquid permeability between the spruce heartwood and sapwood samples of comparable densities, and indicated a similar level of pit aspiration (closure). The common flow path between two cells of conifers occurs through the pits. Still, the sapwood samples had in general a clearly higher water sorption rate than heartwood samples. It could be concluded that the increased sorption was presumably caused by a lowered water surface tension, most likely by a contamination effect of the water by surface-active sapwood extractives rather than differences in morphology of heartwood and sapwood.

However, no clear difference in water absorption and MC levels was seen between coated heartwood and sapwood in the field study or in the accelerated water absorption study. Thus, it is suggested that a coating hinders the surfaceactive extractives to lower the water surface tension, resulting in a similar water absorption behaviour of coated heartwood and sapwood. The influence of density on water sorption of coated spruce was similarly to uncoated spruce, meaning the low-density samples had a higher MC than the high-density samples in the field tests. Furthermore, a one-year weathering of the coated and uncoated samples caused a larger increase in water sorption of high-density heartwood in the accelerated water absorption study.

The field study on uncoated and calcimine-coated spruce showed a higher number of cracks on the high-density samples than on the low-density samples. Additionally, within each density group, a larger number of cracks were seen on sapwood samples as compared to heartwood samples. High-density samples with an alkyd- or an acrylic coating also showed a higher number of cracks. As expected, the formation of cracks on the samples increased their water sorption significantly. The microbial growth was higher on sapwood than on heartwood samples with a white coloured alkyd coating.

The main conclusion is that heartwood and sapwood of different densities influence the water sorption and durability of coated Norway spruce. However, the principles in water sorption of uncoated heartwood and sapwood could not be applied to coated samples. Overall, the results point out that low-density heartwood could be the best material combination to improve the durability of coated spruce in outdoor use. The knowledge acquired in this thesis can enable an increased service life of coated spruce in outdoor use. The increase in service life is achieved by a careful selection of the wood material regarding the proportion of heartwood and to the choice of wood density. As a concluding remark, the role of surface-active spruce extractives needs to be explored, and a follow-up investigation in the context of water sorption is suggested for future research.